Mini VNA Question

[ko4nrbs]

How was the resistance and reactance values determined from the Smith Chart -435m -j48.3m?  What calculations are used to arrive at those values of resistance and reactance?  It's my understanding that the VNA normalizes the resistance and reactance as displayed in the Smith Chart values.

In addition, can the Smith Chart display units be changed.  I have no idea what the m in -435m -j48m repesents.

Thank you,
Bill

[shabaz]

Hi Bill,

(disclaimer: I'm a newcomer to NanoVNA, so please don't assume I know the best method for doing this)

Please see the attached screenshots.
In brief, the values you see on the display at the top are for four traces, all set to S11 in your case, and displayed in various formats.

If you click on Display, you can click on Trace and choose the color of interest (for instance, green in your case, which is displaying the (-453m-j48.3) value). Make sure you don't accidentally gray it out, since that disables the display of it. You can simply tap it again to un-gray it.

Then, click on Back, then select Format S11 (refl), then click on the text Smith. In my screenshot, it's defaulted to impedance (R+jX), not normalized. Yours will be different. You'll see a large selection; you can choose the one of interest.

[ko4nrbs]

Thank you!!
Bill

[pdenisowski]

In addition, can the Smith Chart display units be changed.  I have no idea what the m in -435m -j48m repesents.

I presume "m" stands for milli, so -435m - j48m would be the same as -0.435 - j0.048.

Just a guess:  we do this on some of our instruments (using "m" for "milli-")